My attacker keeps me pinned down. He’s a student, big, white, with close-set eyes and bleached hair in a Caesar cut.

‘Stay down,’ he snarls.

His thick, veiny neck is within reach of my teeth. Blood pulsing just beneath the surface. So many vulnerable tubes in there. The carotid, the jugular, the trachea, the oesophagus. Instinct takes over. Without thinking, I open my mouth and—

‘FBI. Get off him, right now.’

The guy looks over at Thistle, who has a stun gun levelled on him. He climbs off me and raises his hands. ‘Whoa! I didn’t do anything. I was trying to help.’

The bloodlust recedes back to low tide. I stand up, shaking. I almost killed that guy.

A crowd of onlookers has gathered. A few are filming with their phones from a safe distance. Luxford is gone.

‘Shoot as much video as you like,’ Thistle shouts, ‘but uploading even a single second of it will be considered obstruction of justice. You got that?’

It’s a misdemeanour at worst, punishable only by a fine. But the grumbling students put away their phones. No point filming something if they can’t show it to anyone.

‘You all right, Blake?’ Thistle asks.

‘He went that way,’ I say, and start to run towards the parking lot.

Thistle overtakes me quickly. Her breathing doesn’t sound as ragged as mine; all FBI agents have to pass a fitness test where they run three hundred yards in fifty seconds.

When she gets to the parking lot, she doesn’t pause to scan the parked vehicles—she keeps running up the campus driveway, maybe hoping to spot a retreating car.

I can taste my own blood at the back of my throat, so I stop running when I reach the lot. I look around at the parked cars. No one in any of them. I flop down on the asphalt. No one hiding behind or underneath. I can’t see any clues to identify Luxford’s vehicle.

This is a disaster. If the police don’t catch him, I’ll never get to find out what he knows. If they do, they’ll find out his secrets, which could lead them to where Biggs died, which might then lead them to me.

Assuming he knows anything at all. I can’t see a connection between his collection of homemade porn and Biggs’s death.

Thistle’s coming back. ‘He’s gone,’ she says.

•

We’re halfway to Biggs’s apartment when my phone starts buzzing in my pocket.

It’s the burner Charlie Warner gave me. The one I’m supposed to keep on my person at all times.

I don’t want Warner to know that I’m working for the FBI again, and I definitely can’t let Thistle realise that I’m working for Warner.

‘You gonna get that?’ Thistle asks.